1. Field of the Invention
The invention relates to an inking device for a rotary printing machine with a screen roller having an ink supply device arranged on the screen roller. The ink supply device is sealed by blades positioned parallel to a longitudinal axis of the screen roller. The ink supply device supplies printing ink to the circumferential surface of the screen roller and carries away ink that is unabsorbed by or wiped away from the screen roller.
2. Description of the Related Art
A prior art rinsing inking device for a rotary printing machine is disclosed in German reference DE 39 11 839 A1. The prior art rinsing inking device interacts with a screen roller. A closed chamber is arranged below the screen roller bounded by blades on both sides on a circumferential surface of the screen roller. A supply device positioned between the two blades inside the chamber for supplying printing ink under a slight overpressure in an ink application channel. The edges of the supply device bordering the screen roller are separated from the screen roller on both sides. Printing ink that is not pressed from the ink application strip into cups of the screen roller and that drips on the outside of the ink application channel, is conveyed under overpressure to an ink tank by a suction device.
A disadvantage of the inking device known from DE 39 11 839 A1 is that ink supplied from the ink application channel but not absorbed by the cups of the screen roller is not fed back to the ink supply system and is lost.
A prior art distribution device for printing ink is disclosed in German reference DE 33 26 228 A1. The distribution device includes an ink tank forming an air-tight seal connected to a line, from which printing ink is sprayed under pressure onto inking device rollers. The pressure is produced by a pressurized air source that is connected to the ink tank. A prefabricated cartridge containing the printing ink is insertable in the interior of the tank.
The disadvantage of this ink supply system is that it is open. When the ink is sprayed out, not only are the inking device rollers inked, but the surrounding environment is contaminated as well. This necessitates expensive cleaning and a high consumption of cleaning agents. Changing the ink takes a correspondingly long time, and a large amount of ink is lost during the ink change process.